<span>The chemical formula of Helium is He.
Question 1 :
Given n = 1.11 x 10^-6
To get no. of the particle,
No of particle = no. of mole x Avogadro Constant
p = n x NA
1 mol of Helium = 6.02 x 10^23
No of atoms = (6.02 x 10^23) x (1.11 x 10^-6)
= 6.66 x 10^17
................................
Question 2 :
Given p = 4.29x10^21
p = n x NA
4.29 x 10^21 = n x (6.02 x 10^23)
(4.29 x 10^21) / (6.02 x 10^23) = n
n = Approximately 7.126 x 10^-3
Hope the answer is right :)</span>
Answer : The volume for 6.0m HCl solution required = 62.5 ml
Solution : Given,
Initial concentration of HCl solution = 6.0m
Final concentration of HCl solution = 1.5m
Final volume of HCl solution = 250 ml
Initial volume of HCl solution = ?
Formula used for dilution is,

where,
= initial concentration
= final concentration
= initial volume
= final volume
Now put all the given values in above formula, we get the initial volume of HCl solution.

= 62.5 ml
Therefore, the volume for 6.0m HCl solution required = 62.5 ml
How many grams Nitrogen in 1 mol? The answer is 14.0067. We assume you are converting between grams Nitrogen and mole. You can view more details on each measurement unit: molecular weight of Nitrogen or mol The molecular formula for Nitrogen is N. The SI base unit for amount of substance is the mole. 1 grams Nitrogen is equal to 0.071394404106606 mole. Note that rounding errors may occur, so always check the results. Use this page to learn how to convert between grams Nitrogen and mole. Type in your own numbers in the form to convert the units!
Answer is b. Hope it help